John Chua's Algebra Post

How to Solve One Step Equations
Solving By Inspection
2+n=4
First thing we do is isolate the variable
2+(-2)n=4-2
Now we have to balance the equation, so what ever you do on the right side you do on the other side or vice versa.
so the answer is 2, so we put
n=2.
Next thing you do after you get your answer is to verify your answer
2+n=4
2+(2)= 4
4=4 since their equal that means you got the right answer.

Solving with algebra tiles




Two step equation

Solving by inspection
2x+1=5
First thing we have do is cancel constant with opposites
2x+1-1=5-1
2x=4
Now, we have to simply the variable to 2x
2x/2=4/2
x=2
After we find the answer, we must verify it.
2x+1=5 2(2)+1=5
(4)+1=5
5=5.
Solving Using Algebra Tiles

John's Great Book Of Integers

Chapter 1- Grade 7 integer review

-6 - (-4)= -2


-10+6= -4


6-7+2= 1


14-(-3)= 4


-3-(-7)= 4



-3-7= - 10




3+7=10




-3+7=4


Chapter 2- Multiplying Integers

Examples for todays class

(+2)(+3).... 2 groups of +(3) = +6

(-2)(-3)...... remove -2 groups of -3 = +6

(+2)(-3)...... 2 groups of (-3) = -6

(-2)(+3)....... remove -2 groups of (+3)


Chapter 3- Dividing Integers

Even : When you have a even number of negative factors your product is positive.

Odd :When you have a odd number of negative factors your product is negative.

Partitive Division : when you use groups to find your quotient.

6 \ 2 =3

(-6) / (-2)

Quotative Division - sharing a certain number between a given value.

ex.

(-6) / 2 = -3

Sign Rule

In a division question if there is an even amount or no (-) the answer will be a positive

In a division question if there is a odd amount of (-) the answer will be negative

Chapter 4: order of operations

(+6) x (-2) + (-6) ÷ (+2)= +15 (how to get answer)

(-6) ÷ (+2) = -3
[(+6) x (-2)] = (-3)
-12 + (-3) = -15

order :
1. brackets (square brackets)
2. division
3.multiplication
4.addition
5. subtraction.

Term 2 Reflection

TERM 2 REFLECTION
In this term I did very well on all the things I learned examples are.. Pythagoras, percents,surface area and volume.I did well on all of this things because I asked questions when I wasn’t sure what to do and I studied and pretty much did what I had to do.But what I really liked learning about was surface areas and volume because it was easy once you know the formula and its fun challenging yourself by trying.Percent was easy too because I learned a very useful skill when shopping and when figuring out grades. I would really say that I did very well this term.
I kind of struggled on percents because you need to learn a lot like how to find the dollars per second or km/hours.
Next term I will study more and practice more so I can do better next term, I would probably ask more questions.
In percents I learned how to find the sale price, for surface area I learned how to find the areas of different kinds of shapes like triangles and find areas of 3d shapes, for volume I learned how to find volumes of different shapes very similar to surface area but different formula.
The difference between surface area and volume are that surface are is that there are different formulas involve but the thing they have in common is that they both have a method of finding the inside space of a shape.

John Chua's textbook work : volume pages 259-260 #7,12,14

Formula used:
Area of the base x height
b x h1 x h2= volume

A)
7 x 7 / 2 = 24.5cm squared
24.5cm squared x 12 = 294cm cubed

B)
8.1 x 2.2 / 2 = 8.91m squared
8.91 x 15 = 133.65m cubed

C)
320 x 210 = 33,600mm squared
33,600 x 400 = 13 440 000mm cubed





A) height of prism (cm) = 10
how?
7 x 2 / 2= 7cm squared
70 / 7 = 10cm

B) height of triangle (cm) = 12
how?
1080 / 10= 180cm
180 x 2 = 216cm
216 /18 = 12cm

C)base(cm)=20
700 / 5 =140
140 x 2 =280
280 / 14 = 20





volume= 4800cm cubed]
how?
b x h1 x h2= volume
8x 15 / 2= 60cm squared
60cm squared x 80 = 4800cm cubed

Cylinder and Volume Problems



A)3x4x4=48cm^2
48cm^2 x 10cm= 480cm^3

b)3.14 x 4.1 x 4.1=53cm^2
53cm^2 x 11 = 583cm^3



R=d/2
R=10/2
R=5
R=8/2
R=4

outside radius 5cm
inside radius 4cm
height 40cm

pi x r x r = area of base

3.14 x 5 x 5 = 78.5cm^2
78.5cm^2 x 40 cm=3,140 <---- Outside Volume 3.14 x 4 x 4 = 50.24^2 50.24cm^2 x 40cm = 2009.6cm^3 <-------- Inside Volume 3140cm^3-2009.6cm^3= 1,130.4cm^3

Final Percent Post

PERCENT:

1)Percent- means it is out of a hundred or another name for hundredths, it can be also represented as a fraction or a decimal
eg. 65% means 65 out of a 100 or 65/100 or o.65.

REPRESENTING PERCENTS:

A Percent can be represented on a hundred grid.
for example 13%



FRACTIONS, DECIMALS AND PERCENTS:

Percents can be written as a decimal or a fraction
for example:
1/2= 50% , 15%= 0.15

PERCENT OF A NUMBER:

You can use mental math strategies such as doubling, halving, and dividing by ten to find the percent of some numbers.
For example: 12 1/2% of 50 = 0.125 x 50= 6.25

COMBINING PERCENTS:

Percents can be combing by adding to solve problems. eg.
5% + 7% = 12%

You can add the combined percent amount to the original number to find the increase in a number.
eg.
12% of 100= 0.12 x 100 =12
100+ 12 =112

You can multiply the original number by a single percent greater than 100.
eg.
112% of 100= 1.12 x 100
=112

Percents of percents can be used to determine amounts that result from consecutive percent increases or decreases.

2

3)Here is a link from my previous percent post---> John873

4)Here is a link to help understand more about percents----> LINK

John Chua's Pay it forward

Part 1:
"Pay It Forward" is a way of helping people without expecting anything in return but to tell them to help 3 other people.It's like inspiring someone who is needs help so that they help other people and the people they help, go the same thing. It is to make the world a better place to live in. This idea came from a movie called "Pay It Forward" where a boy named Trevor gets an assignment to think of way to make the world a better place. His idea is to help three people and those people help Three other people.

Part 2:
My act of kindness was to write a write a letter to a soldier from Afghanistan.I chose this to let a soldier know that we believe in them and to let them know what we think of there actions.I wrote a letter to a soldier. I wrote what I think about them and made them feel good about themselves.
I did my act of kindness today (December 19, 2010)



Part 3 :

I think my act of kindness went very well, it was better than I thought it would go. Everything went well I dropped the letter. I felt very good after I sent the letter, especially when I wrote the letter. I'm not sure how the soldier would feel but i think he would feel appreciated. I did not ask or write pay it forward because I had this feeling that there a soldier they're already doing a lot for our country.

Part 4:
I think that the idea of "Pay It Forward" is important because it's a very good plan to make the world a better place because it showing that it doesn't matter if you get anything in return but the fact that if they help other people means that its good enough. I think my act of kindness made a difference in a way because not a lot of people are sending letters to soldier thanking them for their sacrifice.

John Chua's scribe post

Understanding percents.
DEFINITIONS:
Percent- means it is out of a hundred or another name for hundredths
eg. 65% means 65 out of a 100 or 65/100 or o.65

Fractional percent- a percent that includes a portion of a percent.
eg. 1/2%, 0.42%, 7 3/8%, 125 3/4%, 4.5%

SHOW YOU KNOW:
page 125

A) 248% B)1/4% C)74 8/10%
Page 127



A)


B)

C)

John's Pythagoras Scribe Post

Textbook Pages 98-100

#1 and 17

1.Explain how to estimate √28 to one decimal place without using a calculator.compare your answer with a classmate's

Answer:

To estimate √28 you have to find the two closest perfect squares. 25 and 36 are just right because 28 is between these two perfect squares. There are two method or ways to find the estimate of the square root of 28

The first one is a number line

HOW?

What I did was put the perfect squares on both ends of the number line and then I decided which is closest 28 which was 25 and I took a guesstimate and I got 5.3

Other way is this

HOW!?

The method is the same as the number line except you write it different. You just find what number 28 is closest to which is 25 and take a guesstimate that would be logical not over 5.5 since its closest to 25.

18.

a) Evaluate √9.

b) Estimate the square root of your answer

in part a), to one decimal place.

c) Use a calculator to check your estimate.

Express your answer to the nearest

hundredth.

d) How close is your estimate in part b)

to your calculation in part c)?

A)How to find the square root of 9? 9 is a perfect square so its easy, what I did was I looked for other perfect squares that are closest to 9 like 4 and 16 so 4 is 2x2 and 16 is 4x4 so 9 is 3x3 since its in the middle of 2 and 4

B)

C) The calculation is 1.73

D)My estimation in Part b was 0.2 larger than the actual calculation.

(HEY GUYS IF YOU FIND ANY MISTAKE, LEAVE A COMMENT AND PUT THE RIGHT ANSWER)

JOHN'S SESAME STREET VIDEO POST

Group Members: John C., Alec M., Mark C., Brandon A.

Part One:
Two term ratios and Three term ratio- compares two or three quantities measured in the same units.
Example: Two term ratios, orange balls to purple balls 3:5
Three term ratios, orange balls to red balls to purple balls 3:2:5

Rates- compares two quantities measured in different units.
example: $/orange= $1.99/orange

Proportional reasoning- a relationship that says two ratios or rates are equal
example: x2
$/h $50/1h = $100/2h
x2

Part Two:

bf4c4ef4-16fc-406c-93e0-41a9557fb70c

1.03.01

Description: Lefty the salesman sells Ernie an "8"

Part Three:
Wanna buy a rate?

John Chua's Math Profile

Hi my name is John Chua. I am a grade 8 math student. If someone asked me "Do you like math?" I would tell them I kinda like it because it can really be fun at times. The best thing I did in math class was learning the times table, I like this because when I was in grade 1 the teacher told us to memorize the times table and we would present to them, if we got it all right we would get a some stickers.

The best unit I studied last year was probability. I think I did well in this unit because after i knew what it meant or how to do it it was pretty easy to do. The unit i struggled with last year was transformations, the part i struggled with was the rotation, I didn't really know how to rotate properly so I almost failed the test. This year i would listen to the teacher and ask questions if i don't get it, so i wouldn't struggle that much.

Now that I'm in grade 8 , I would be organized and study harder for all my test and quizzes. I will do all my homework and finish it on time to be a successful math student.This year I want to learn about algebra, even though its kinda hard I just want to learn it so in grade 9, I'll know what to do.

I was a blogger last year. My favorite post that I created was exam review for circles. I like this one because I really worked hard on this and I had to draw pictures using paint and I think I explained everything well. Blogging helped me a lot, it helped me how to be organize my notes and how to work diligently, I learned how to do blogs, and helped me to listen attentively to my teacher. This year I want to continue what I know about blogging and learn even more stuff.